Errors running builder ‘Java Builder’

Hello, after a number of days working in a workspace the Java Builder stops functioning. I get now visual queue that this is happening except that my “rebuilt” code no longer shows the changes I’ve made. When I look in the Error view I see 20+ errors for each execution of a Project->Clean. The stack trace is shown below. The errors vary, but are mostly “Errors running builder ‘Java Builder’ on project….” and Problems occurred when invoking code from plug-in: “org.eclipse.core.resources”. This is the 3rd time this has happened to me. Each time I create a new workspace, import my projects and everything works fine (until it happens again…). Below the stack trace I’ve included my installation details. Thanks for any help you can provide as this is a real productivity sink.

-Nate

java.lang.NullPointerException
at org.maven.ide.eclipse.jdt.internal.JDTCompilationParticipant.cleanStarting(JDTCompilationParticipant.java:45)
at org.eclipse.jdt.internal.core.builder.BatchImageBuilder.cleanOutputFolders(BatchImageBuilder.java:91)
at org.eclipse.jdt.internal.core.builder.BatchImageBuilder.build(BatchImageBuilder.java:46)
at org.eclipse.jdt.internal.core.builder.JavaBuilder.buildAll(JavaBuilder.java:254)
at org.eclipse.jdt.internal.core.builder.JavaBuilder.build(JavaBuilder.java:173)
at org.eclipse.core.internal.events.BuildManager$2.run(BuildManager.java:633)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:37)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:170)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:201)
at org.eclipse.core.internal.events.BuildManager$1.run(BuildManager.java:253)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:37)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:256)
at org.eclipse.core.internal.events.BuildManager.basicBuildLoop(BuildManager.java:309)
at org.eclipse.core.internal.events.BuildManager.build(BuildManager.java:341)
at org.eclipse.core.internal.events.AutoBuildJob.doBuild(AutoBuildJob.java:140)
at org.eclipse.core.internal.events.AutoBuildJob.run(AutoBuildJob.java:238)
at org.eclipse.core.internal.jobs.Worker.run(Worker.java:55)

*** Date:
Wednesday, May 27, 2009 9:20:59 AM EDT

** System properties:
OS=WindowsXP
OS version=5.1.0
Java version=1.5.0_11

*** MyEclipse details:
MyEclipse Blue Edition
Version: 7.1.1 Blue
Build id: 7.1.1-Blue-20090310

*** Eclipse details:
MyEclipse Blue Edition

Version: 7.1.1 Blue
Build id: 7.1.1-Blue-20090310

Eclipse Platform

Version: 3.4.1.r341_v20080731-9I96EiDElYevwz-p1bP5z-NlAaP7vtX6Utotqsu
Build id: M20080911-1700

Eclipse Java Development Tools

Version: 3.4.1.r341_v20080709-0800-7o7tEAfEF_U5qyUgrb2HAp539P97
Build id: M20080709-0800

Eclipse Graphical Editing Framework GEF

Version: 3.4.1.v20080806-67718083A56B4H2A3213573
Build id: 200809101400

Eclipse RCP

Version: 3.4.100.r341_v20080814-989JESIEdAciFYfkZZsBfSwQ2341
Build id: M20080703-0800

Eclipse Plug-in Development Environment

Version: 3.4.1.r341_v20080731-7T7U0E9mlRIuGUYviF_VP
Build id: M20080703-0800

Eclipse startup command=-os
win32
-ws
win32
-arch
x86
-showsplash
-launcher
C:\Program Files\Genuitec\MyEclipse 7.1 Blue Edition\myeclipse-blue.exe
-name
Myeclipse-blue
–launcher.library
C:\Program Files\Genuitec\MyEclipse 7.1 Blue Edition\../Common\plugins\org.eclipse.equinox.launcher.win32.win32.x86_1.0.101.R34x_v20080731\eclipse_1115.dll
-startup
C:\Program Files\Genuitec\MyEclipse 7.1 Blue Edition\../Common\plugins\org.eclipse.equinox.launcher_1.0.101.R34x_v20080819.jar
-clean
-configuration
C:\Program Files\Genuitec\MyEclipse 7.1 Blue Edition\configuration
-clean
-vm
C:\Program Files\Genuitec\Common\binary\com.sun.java.jre.win32.x86_1.5.0.011\bin\client\jvm.dll